WHEN Barack Obama first ran for president, Emma Hamilton was part of that politically crucial cohort, the white working class. A tall woman with tawny hair, broad shoulders, a firm handshake and a forthright, direct manner, Ms Hamilton worked as a loader at a factory in Sumter, a modest city of 40,000 in east-central South Carolina. In July 2008, however, after seven years on the factory floor, she mangled her hand between two heavy rollers. The accident was to leave her unable to work.

She lost her house three years later, in April 2011. She, her 20-year-old son and her dog moved into her teal Chevy van, where they have been living ever since, collecting metal cans during the day and sleeping in a grocery-store car park at night.

When a pain in Ms Hamilton’s leg grew too severe to ignore, an employee at the shelter where she and her son occasionally stay directed her to the Excelsior Medical Clinic in downtown Sumter. The assistant who checked her in was named Patricia Dunham. Ms Dunham has cinnamon-coloured skin, arresting blue eyes and an easy, infectious laugh. She works at the Excelsior for 37.5 hours each week. At night she works behind the counter at a fast-food restaurant. The first job pays $12.50 an hour, the second $7.25, the federal minimum wage. If she could rely on 24 hours a week at the restaurant--which is what she would like--she would earn $32,137.50 for working 61.5 hours a week, 50 weeks a year, before tax witholdings.